A trailer was stolen from Brunel Close, Daventry overnight on Friday, July 31.
Offenders gained access to a secure yard and stole the trailer sometime between 5.15pm on Friday and 8.45am on Saturday, 1 August.
The offenders than broke the locks on the gates of the yard and made off.
Police would like to speak to anyone who may have witnessed anyone acting suspiciously in the Brunel Close area of Daventry on Friday night or the early hours of Saturday morning.
They would also like to speak to anyone who may have been offered the trailer, pictured, for sale.
Witnesses or anyone with information about this incident is asked to contact police on 101 or independent charity Crimestoppers anonymously on 0800 555 111.